When manufacturing a semiconductor device, a word line, it is necessarily required to implement various fine patterns such as a digit line, a contact and the like. A lithograph technology has been generally applied to form these fine patterns.
A contact lithograph method which has been traditionally and widely used enables the pattern to be formed throughout a wide area. However, due to a limit of the diffraction of light, it was problematic that a pitch of the fine pattern which can be formed is limited (1˜2 μm).
Accordingly, to solve this problem, a stepper method, a scanner method, a holographic lithography method and the like were developed. However, these methods need complicated and sophisticated equipment and incur high expenses. Further, the methods have a limit in view of the fact that an area which can form a pattern is limited. That is, the conventional lithograph method is basically limited to implement nonoscale fine patterns due to the problems such as a limitation of equipment or a process property. More specifically, upon the use of the conventional lithography technology, it would be difficult to implement nanoscale patterns which are uniformly formed throughout a large area of more than 8 inch.
According to the aforesaid problems, a method of forming a porous metal thin film using a porous template made of a metal material as disclosed in Korean Laid-Open Patent Publication No. 2011-0024892, and forming nano patterns using the porous metal thin film as a catalyst was suggested. The method was problematic in that because the porous template should be prepared in advance, it is inconvenient to use the method, and because a catalyst growth method is used, nano patterns can be formed at only desired regions. Moreover, it was problematic that the nano patterns cannot be formed on a transparent substrate.